The \(X(3872)\)  is a narrow resonance close to the \(D^0\bar{D}^{*0}\)  threshold,
which was first observed in \(B^{\pm }\rightarrow K^{\pm } J/\psi \pi ^+\pi ^-\) 
by the BELLE Collaboration [1]},
and later confirmed by CDF [2]}, D0 [3]}
and BABAR Collaborations [4]}.
It has also been observed at LHCb [5]} and CMS [6]}.
The new results of Belle show a mass
\(m_{X(3872)}=3871.85 \pm 0.27(stat.)\pm 0.19(syst.)\)  MeV
and width less than \(1.2\)  MeV [7]}.
A recent angular distribution analysis of the \(X\rightarrow J/\Psi \pi ^+\pi ^-\)  decay
by LHCb has determined the \(X(3872)\)  quantum numbers to be \(J^{PC}=1^{++}\)  [8]}.
